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Re: RDF Semantics: partial review

From: pat hayes <phayes@ihmc.us>
Date: Fri, 7 Nov 2003 16:54:06 -0600
Message-Id: <p06001f70bbd16c41f559@[10.1.31.1]>
To: herman.ter.horst@philips.com
Cc: www-rdf-comments@w3.org

>  >>
>>>"A name is from a vocabulary if ..."
>  >>I hope that this can be simplified.
>>

....

>I continue to think that the terminology 'from V'
>as being different from 'in V' is very confusing.
>It seems that people will typically identify the two
>notions.

.....

>)
>
>I would suggest to omit the terminology 'from V'.

I agree that the in/from/of contrast may be too delicate and is not 
really needed in any case.

Let me suggest that I adopt the following simplified convention, 
which I think will be sufficient. A name (as now) is a URI or typed 
literal. A vocabulary is a set of names. The vocabulary OF a graph is 
the set of names that occur in the graph as the subject, object or 
predicate of a triple. Interpretations are defined on a vocabulary, 
usually that of a graph.

Note, this excludes the URIs inside typed literals. Since IL applies 
directly to typed literals, this will be of consequence only when we 
consider datatyping explicitly, and in that case the requirement that 
datatypes be 'declared' by a triple

ddd rdf:type rdfs:Datatype .

is sufficient to ensure that all the required URIs are part of the 
graph vocabulary. (rdf:XMLLiteral is part of the rdfV vocabulary). So 
I think in fact there is no need to even consider the names inside 
typed literals when describing simple, RDF and RDFS entailment.

This approach has the merits of simplicity and of treating all nodes 
uniformly, which is more conventional in any case.

>
>[...]
>
>>
>>>As to lines 1 and 2 of these tables: I believe
>>>that clarification would be helpful.
>>>line 1 says: if E is a plain literal "aaa" then I(E)=aaa.
>>>String quotes are removed from "aaa", but it seems that I(E) is a
>>>string.  What is the definition here?
>>
>>The tables are all stated using the N-triples conventions. In this,
>>literal character strings are enclosed inside double quote marks. So
>>aaa here indicates the character string.
>
>Thank you for the explanation.  I think that it would be helpful
>to include this here in the document.

Done.

>
>[...]
>
>>
>>>==
>>>
>>>Section 1.5
>>>
>>>the table: Semantic conditions for blank nodes
>>>
>>>It seems that line 1 would need to be replaced by
>>>something like the following more complete statement:
>>>-  If A is a mapping defined on the blank node E, then
>>>     I+A(E)=A(E).
>>
>>I don't feel that that is necessary.
>>
>
>You cannot speak of A(E) unless it is defined.

Oh, come. A is a mapping: A(E) is the result of applying that mapping 
to E.  Do I really need to *define* what is meant by applying a 
mapping to an argument? You will want me to be defining the meaning 
of the word "and" next.

>  >
>>Fixed. I seem to have a localized dyslexia for that particular word.
>>
>
>I found another occurence of this typo in the document,
>two paragraphs below the rdfs entailment lemma.
>
>
>Other typos (in new text from yesterday):
>themsleves
>intepretation

OK, thanks, now fixed.

Pat
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Received on Friday, 7 November 2003 17:54:08 GMT

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